The present invention is generally related to the field of integrated circuit fabrication and, more particularly, is related to an apparatus and method for the automated handling and testing of optical integrated circuits.
The electronics industry currently produces thousands of integrated circuits each day. These circuits have come down in cost significantly in more recent years due to the use of effective mass production techniques that facilitate the current high output. The machinery employed in these mass production techniques is quite complex and often performs repetitive tasks. Such machinery is typically engineered for maximum reliability over a large number of operation cycles, whatever the specific operation may entail.
In addition to the use of automated machines to produce various integrated circuits, industry also employs automated machines to test the integrated circuits to ensure maximum reliability and quality of the end product. Due to the high volumes created, such testing equipment is designed with the goal in mind to operate with maximum efficiency over numerous cycles without failure. However, some testing systems fall short of this goal.
For example, in testing one particular type of integrated circuit, namely, an active pixel sensor, machines are employed to pick up the sensor and place it on a test circuit such that the leads of the sensor come into contact with electrical pads through which the sensor may be tested. Such sensors require that light be applied to their light sensitive surface to determine whether the response of the sensor is within acceptable parameters.
However, typical pick-up devices employed to handle such sensors do not provide an ability to both hold the sensor and apply light to the light sensitive surface. In particular, suction cups that are typically used in such handling equipment generally cover the light sensitive surfaces and a proper test may not be performed when such handlers place the sensor against the appropriate test pads.
To solve this problem, some have attempted to use suction devices that allow light to illuminate the light sensitive surfaces. However, such machinery has proven unreliable. In particular, such pick-up machines cannot effectively create a reliable vacuum seal with the integrated circuit that allows light to be applied to the light sensitive surfaces over an acceptable number of testing cycles.
In light of the foregoing, the present invention provides an apparatus and method for picking up an integrated circuit that facilitates optical testing thereof. Briefly described, the apparatus comprises a pick-up mechanism that includes a vacuum chamber. The vacuum chamber is defined by an upper portion, an expandable member, and a lower portion. The lower portion defines a suction orifice that is moveable with a movement of the expandable member. An optical pathway is defined by the vacuum chamber, the optical pathway passing through the suction orifice and onto an integrated circuit that is held against the suction orifice via a vacuum pressure applied to the vacuum chamber.
During operation, the suction orifice is applied to a surface of the integrated circuit and the vacuum is applied to the vacuum chamber, thereby applying a suction hold to the integrated circuit. The expandable member contracts, thereby moving the suction orifice in an axial direction until the integrated circuit comes into contact with a number of contact edges that stop the movement. The expandable member may be, for example, a bellows or other similar device as an integral portion of the vacuum chamber.
The present invention can also be viewed as providing a method for picking up and testing an integrated circuit. In this regard, the method can be broadly summarized by the following steps: providing a vacuum chamber having an upper portion, an expandable member, and a lower portion, the lower portion defining a suction orifice, the suction orifice being moveable with a movement of the expandable member; applying the suction orifice to a smooth face of an integrated circuit; evacuating the vacuum chamber to pick up the integrated circuit; and illuminating the smooth face of the integrated circuit with a light that propagates along an optical pathway that passes through the suction orifice.
The present invention has numerous advantages, including the movement of the suction orifice that accommodates the use of a more rigid O-ring that provides greater durability and reliability in operation. The movement of the suction orifice also allows the pick-up mechanism to be employed with integrated circuits of varying height with the less durable O-ring. In addition, due to the flexibility of the O-ring and the fact that it is frictionally mounted into the O-ring groove, it is easily replaced by hand when worn, etc. Also, the frictional mounting of the O-ring keeps it in place in the O-ring groove and it does not move into the optical pathway in any way. In addition, the pick-up mechanism allows the automated testing of active pixel sensors, for example, by applying light to the sensor while it is held by the pick-up mechanism which places the sensor over test pads for testing. Also, the over all design of the pick-up mechanism is simple, user friendly, robust and reliable in operation, efficient in operation, and easily implemented for mass commercial production.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention.